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  Subjects -> ENGINEERING (Total: 1957 journals)
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ENGINEERING (1124 journals)            First | 4 5 6 7 8 9 10 11 | Last

Journal of Nanoparticle Research     Hybrid Journal   (3 followers)
Journal of Nanoscience     Open Access  
Journal of Nanoscience and Nanotechnology     Full-text available via subscription   (11 followers)
Journal of NanoScience, NanoEngineering & Applications     Full-text available via subscription  
Journal of Nanotechnology     Open Access   (2 followers)
Journal of Nanotechnology in Engineering and Medicine     Full-text available via subscription   (5 followers)
Journal of Natural Gas Science and Engineering     Hybrid Journal   (3 followers)
Journal of Near Infrared Spectroscopy     Full-text available via subscription   (7 followers)
Journal of Networks     Open Access   (3 followers)
Journal of Oceanography and Marine Science     Open Access   (1 follower)
Journal of Operations Management     Hybrid Journal   (12 followers)
Journal of Optics     Hybrid Journal   (2 followers)
Journal of Organizational Behavior     Hybrid Journal   (17 followers)
Journal of Petroleum Science Research     Open Access   (1 follower)
Journal of Phase Equilibria and Diffusion     Hybrid Journal  
Journal of Power Sources     Partially Free   (20 followers)
Journal of Pre-College Engineering Education Research     Open Access  
Journal of Pressure Vessel Technology     Full-text available via subscription   (8 followers)
Journal of Professional Issues in Engineering Education and Practice     Full-text available via subscription   (6 followers)
Journal of Quality and Reliability Engineering     Open Access  
Journal of Quality in Maintenance Engineering     Hybrid Journal   (3 followers)
Journal of Radiation Research and Applied Sciences     Open Access   (1 follower)
Journal of Rare Earths     Full-text available via subscription   (1 follower)
Journal of Real-Time Image Processing     Hybrid Journal   (5 followers)
Journal of Regional Science     Hybrid Journal   (6 followers)
Journal of Reinforced Plastics and Composites     Hybrid Journal   (3 followers)
Journal of Research of NIST     Open Access   (1 follower)
Journal of Rock Mechanics and Geotechnical Engineering     Open Access   (1 follower)
Journal of Russian Laser Research     Hybrid Journal  
Journal of Safety Engineering     Open Access   (3 followers)
Journal of Safety Research     Hybrid Journal   (4 followers)
Journal of Science and Technology     Open Access  
Journal of Science and Technology (Ghana)     Open Access   (1 follower)
Journal of Science and Technology Policy Management     Hybrid Journal   (2 followers)
Journal of Scientific Computing     Hybrid Journal   (3 followers)
Journal of Scientific Innovations for Development     Open Access   (1 follower)
Journal of Semiconductors     Full-text available via subscription   (2 followers)
Journal of Sensor Technology     Open Access   (2 followers)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Sol-Gel Science and Technology     Hybrid Journal   (2 followers)
Journal of Solar Energy     Open Access   (1 follower)
Journal of Solar Energy Engineering     Full-text available via subscription   (13 followers)
Journal of Superconductivity and Novel Magnetism     Partially Free   (1 follower)
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques     Hybrid Journal   (1 follower)
Journal of Surveying Engineering     Full-text available via subscription   (6 followers)
Journal of Technology Management & Innovation     Open Access   (1 follower)
Journal of Telecommunications Management     Full-text available via subscription   (2 followers)
Journal of Testing and Evaluation     Full-text available via subscription   (9 followers)
Journal of the Air & Waste Management Association     Hybrid Journal   (2 followers)
Journal of the Chinese Institute of Engineers     Hybrid Journal  
Journal of the Chinese Institute of Industrial Engineers     Hybrid Journal   (1 follower)
Journal of the Franklin Institute     Full-text available via subscription   (2 followers)
Journal of the Institution of Engineers (India ): Series D     Hybrid Journal  
Journal of the Institution of Engineers (India) : Series B     Hybrid Journal   (1 follower)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal  
Journal of the Institution of Engineers (India): Series A     Hybrid Journal  
Journal of the Institution of Engineers (India): Series C     Hybrid Journal   (1 follower)
Journal of the National Science Foundation of Sri Lanka     Open Access   (1 follower)
Journal of the University of Ruhuna     Open Access  
Journal of Thermal Science and Engineering Applications     Full-text available via subscription   (1 follower)
Journal of Thermal Stresses     Hybrid Journal   (2 followers)
Journal of Transplantation     Open Access   (3 followers)
Journal of Transport and Supply Chain Management     Open Access   (4 followers)
Journal of Transportation Engineering     Full-text available via subscription   (13 followers)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (11 followers)
Journal of Tribology     Full-text available via subscription   (8 followers)
Journal of Turbomachinery     Full-text available via subscription   (6 followers)
Journal of Turbulence     Hybrid Journal  
Journal of Unmanned Vehicle Systems     Full-text available via subscription  
Journal of Urban and Environmental Engineering     Open Access  
Journal of Urban Planning and Development     Full-text available via subscription   (27 followers)
Journal of Urban Regeneration and Renewal     Full-text available via subscription   (9 followers)
Journal of Vibration and Acoustics     Full-text available via subscription   (19 followers)
Journal of Visualization     Hybrid Journal  
Journal of Volcanology and Seismology     Hybrid Journal   (1 follower)
Journal of Wuhan University of Technology-Mater. Sci. Ed.     Hybrid Journal  
Journal of X-Ray Science and Technology     Hybrid Journal  
Journal of Zhejiang University SCIENCE A     Hybrid Journal  
Journal on Chain and Network Science     Full-text available via subscription   (2 followers)
Jurnal Teknologi     Open Access   (1 follower)
Karaelmas Science and Engineering Journal     Open Access  
Kleio     Full-text available via subscription   (2 followers)
Landscape and Ecological Engineering     Hybrid Journal   (3 followers)
Langmuir     Full-text available via subscription   (35 followers)
Leadership and Management in Engineering     Full-text available via subscription   (8 followers)
Learning Technologies, IEEE Transactions on     Hybrid Journal   (9 followers)
Lighting Research and Technology     Hybrid Journal  
Logic and Analysis     Hybrid Journal  
Logica Universalis     Hybrid Journal  
Lubrication Science     Hybrid Journal  
Machines     Open Access  
Machining Science and Technology: An International Journal     Hybrid Journal   (3 followers)
Macromolecular Reaction Engineering     Hybrid Journal  
Magazine of Concrete Research     Hybrid Journal   (4 followers)
Magdeburger Journal zur Sicherheitsforschung     Open Access  
Magnetics Letters, IEEE     Hybrid Journal   (1 follower)
Management and Production Engineering Review     Open Access  
Management Science and Engineering     Open Access   (1 follower)
Manufacturing Engineer     Hybrid Journal   (5 followers)
Manufacturing Research and Technology     Full-text available via subscription   (5 followers)

  First | 4 5 6 7 8 9 10 11 | Last

Physica D: Nonlinear Phenomena    [5 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0167-2789
     Published by Elsevier Homepage  [2556 journals]   [SJR: 0.976]   [H-I: 83]
  • Discontinuity-induced bifurcation cascades in flows and maps with
           application to models of the yeast cell cycle
    • Abstract: Publication date: 15 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 271
      Author(s): Mike R. Jeffrey , Harry Dankowicz
      This paper applies methods of numerical continuation analysis to document characteristic bifurcation cascades of limit cycles in piecewise-smooth, hybrid-dynamical-system models of the eukaryotic cell cycle, and associated period-adding cascades in piecewise-defined maps with gaps. A general theory is formulated for the occurrence of such cascades, for example given the existence of a period-two orbit with one point on the system discontinuity and with appropriate constraints on the forward trajectory for nearby initial conditions. In this case, it is found that the bifurcation cascade for nearby parameter values exhibits a scaling relationship governed by the largest-in-magnitude Floquet multiplier, here required to be positive and real, in complete agreement with the characteristic scaling observed in the numerical study. A similar cascade is predicted and observed in the case of a saddle–node bifurcation of a period-two orbit, away from the discontinuity, provided that the associated center manifold is found to intersect the discontinuity transversally.


      PubDate: 2014-01-24T09:09:42Z
       
  • Bouncing dynamics of a spring
    • Abstract: Publication date: Available online 21 January 2014
      Source:Physica D: Nonlinear Phenomena
      Author(s): M. Hubert , F. Ludewig , S. Dorbolo , N. Vandewalle
      We consider the dynamics of a deformable object bouncing on an oscillating plate and we propose to model its deformations. For this purpose, we use a spring linked to a damper. Elastic properties and viscous effects are taken into account. From the bouncing spring equations of motion, we emphasize the relevant parameters of the dynamics. We discuss the range of parameters in which elastic deformations do not influence the bouncing dynamics of this object and compare this behavior with the bouncing ball dynamics. By calculating the spring bouncing threshold, we evidence the effect of resonance and prove that elastic properties can make the bounce easier. This effect is for example encountered in the case of bouncing droplets. We also consider bifurcation diagrams in order to describe the consequences of a dependence on the frequency. Finally, hysteresis in the dynamics is presented.


      PubDate: 2014-01-24T09:09:42Z
       
  • Editorial Board
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270




      PubDate: 2014-01-20T09:08:49Z
       
  • Editorial Board
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269




      PubDate: 2014-01-20T09:08:49Z
       
  • Improving the precision of noisy oscillators
    • Abstract: Publication date: Available online 16 January 2014
      Source:Physica D: Nonlinear Phenomena
      Author(s): Jeff Moehlis
      We consider how the period of an oscillator is affected by white noise, with special attention given to the cases of additive noise and parameter fluctuations. Our treatment is based upon the concepts of isochrons, which extend the notion of the phase of a stable periodic orbit to the basin of attraction of the periodic orbit, and phase response curves, which can be used to understand the geometry of isochrons near the periodic orbit. This includes a derivation of the leading-order effect of noise on the statistics of an oscillator’s period. Several examples are considered in detail, which illustrate the use and validity of the theory, and demonstrate how to improve a noisy oscillator’s precision by appropriately tuning system parameters or operating away from a bifurcation point. It is also shown that appropriately timed impulsive kicks can give further improvements to oscillator precision.


      PubDate: 2014-01-20T09:08:49Z
       
  • An energy–momentum map for the time-reversal symmetric 1:1 resonance
           with Z2×Z2 symmetry
    • Abstract: Publication date: 15 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 271
      Author(s): Giuseppe Pucacco , Antonella Marchesiello
      We present a general analysis of the bifurcation sequences of periodic orbits in general position of a family of reversible 1:1 resonant Hamiltonian normal forms invariant under Z 2 × Z 2 symmetry. The rich structure of these classical systems is investigated both with a singularity theory approach and geometric methods. The geometric approach readily allows to find an energy–momentum map describing the phase space structure of each member of the family and a catastrophe map that captures its global features. Quadrature formulas for the actions, periods and rotation number are also provided.


      PubDate: 2014-01-12T10:30:22Z
       
  • Dynamics of a continuous piecewise affine map of the square
    • Abstract: Publication date: 15 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 271
      Author(s): Georg Ostrovski
      We present a one-parameter family of continuous, piecewise affine, area preserving maps of the square, which are inspired by a dynamical system in game theory. Interested in the coexistence of stochastic and (quasi-)periodic behaviour, we investigate invariant annuli separated by invariant circles. For certain parameter values, we explicitly construct invariant circles both of rational and irrational rotation numbers, and present numerical experiments of the dynamics on the annuli bounded by these circles.


      PubDate: 2014-01-08T10:30:33Z
       
  • Two bump solutions of a homogenized Wilson–Cowan model with periodic
           microstructure
    • Abstract: Publication date: Available online 2 January 2014
      Source:Physica D: Nonlinear Phenomena
      Author(s): Elena Malyutina , John Wyller , Arcady Ponosov
      We study existence and stability of 2-bump solutions of the one-population homogenized Wilson–Cowan model, where the heterogeneity is built in the connectivity functions by assuming periodic modulations in both the synaptic footprint and in the spatial scale. The existence analysis reveals that the generic picture consists of two bumps states for each admissible threshold value for the case when the solutions are independent of the local variable and the firing rate function is modeled as a Heaviside function. A framework for analyzing the stability of 2-bumps is formulated, based on spectral theory for Fredholm integral operators. The stability method deforms to the standard Evans function approach for the translationally invariant case in the limit of no heterogeneity, in a way analogous to the single bump case for the homogenized model. Numerical study of the stability problem reveals that both the broad and narrow bumps are unstable just as in the translationally invariant case when the connectivity function is modeled by means of a wizard hat function. For the damped oscillating connectivity kernel, we give a concrete example of a 2-bump solution which is stable for all admissible values of the heterogeneity parameter.


      PubDate: 2014-01-04T10:32:32Z
       
  • The Swift–Hohenberg equation with a nonlocal nonlinearity
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270
      Author(s): David Morgan , Jonathan H.P. Dawes
      It is well known that aspects of the formation of localised states in a one-dimensional Swift–Hohenberg equation can be described by Ginzburg–Landau-type envelope equations. This paper extends these multiple scales analyses to cases where an additional nonlinear integral term, in the form of a convolution, is present. The presence of a kernel function introduces a new lengthscale into the problem, and this results in additional complexity in both the derivation of envelope equations and in the bifurcation structure. When the kernel is short-range, weakly nonlinear analysis results in envelope equations of standard type but whose coefficients are modified in complicated ways by the nonlinear nonlocal term. Nevertheless, these computations can be formulated quite generally in terms of properties of the Fourier transform of the kernel function. When the lengthscale associated with the kernel is longer, our method leads naturally to the derivation of two different, novel, envelope equations that describe aspects of the dynamics in these new regimes. The first of these contains additional bifurcations, and unexpected loops in the bifurcation diagram. The second of these captures the stretched-out nature of the homoclinic snaking curves that arises due to the nonlocal term.


      PubDate: 2014-01-04T10:32:32Z
       
  • Renormalisation of correlations in a barrier billiard: Quadratic
           irrational trajectories
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270
      Author(s): L.N.C. Adamson , A.H. Osbaldestin
      We present an analysis of autocorrelation functions in symmetric barrier billiards using a renormalisation approach for quadratic irrational trajectories. Depending on the nature of the barrier, this leads to either self-similar or chaotic behaviour. In the self-similar case we give an analysis of the half barrier and present a detailed calculation of the locations, asymptotic heights and signs of the main peaks in the autocorrelation function. Then we consider arbitrary barriers, illustrating that typically these give rise to chaotic correlations of the autocorrelation function which we further represent by showing the invariant sets associated with these correlations. Our main ingredient here is a functional recurrence which has been previously derived and used in work on the Harper equation, strange non-chaotic attractors and a quasi-periodically forced two-level system.


      PubDate: 2013-12-31T10:37:26Z
       
  • A Kushner–Stratonovich Monte Carlo filter applied to nonlinear
           dynamical system identification
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270
      Author(s): S. Sarkar , S.R. Chowdhury , M. Venugopal , R.M. Vasu , D. Roy
      A Monte Carlo filter, based on the idea of averaging over characteristics and fashioned after a particle-based time-discretized approximation to the Kushner–Stratonovich (KS) nonlinear filtering equation, is proposed. A key aspect of the new filter is the gain-like additive update, designed to approximate the innovation integral in the KS equation and implemented through an annealing-type iterative procedure, which is aimed at rendering the innovation (observation–prediction mismatch) for a given time-step to a zero-mean Brownian increment corresponding to the measurement noise. This may be contrasted with the weight-based multiplicative updates in most particle filters that are known to precipitate the numerical problem of weight collapse within a finite-ensemble setting. A study to estimate the a-priori error bounds in the proposed scheme is undertaken. The numerical evidence, presently gathered from the assessed performance of the proposed and a few other competing filters on a class of nonlinear dynamic system identification and target tracking problems, is suggestive of the remarkably improved convergence and accuracy of the new filter.


      PubDate: 2013-12-31T10:37:26Z
       
  • Collective phase dynamics of globally coupled oscillators: Noise-induced
           anti-phase synchronization
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270
      Author(s): Yoji Kawamura
      We formulate a theory for the collective phase description of globally coupled noisy limit-cycle oscillators exhibiting macroscopic rhythms. Collective phase equations describing such macroscopic rhythms are derived by means of a two-step phase reduction. The collective phase sensitivity and collective phase coupling functions, which quantitatively characterize the macroscopic rhythms, are illustrated using three representative models of limit-cycle oscillators. As an important result of the theory, we demonstrate noise-induced anti-phase synchronization between macroscopic rhythms by direct numerical simulations of the three models.


      PubDate: 2013-12-27T16:31:02Z
       
  • Singular continuation of planar central configurations with clusters of
           bodies
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): Kevin A. O’Neil
      Planar central configurations of point masses that have one or more clusters of bodies are created by analytic continuation. The singularity of the gravitational interaction is removed from the continuation equations by algebraic means. The continuation splits a single body into several, and the initial mass of the single body can be nonzero. Necessary conditions are derived for these continuations that may be useful in addressing the question of finiteness of central configurations.


      PubDate: 2013-12-23T10:30:21Z
       
  • Numerical simulation of piecewise-linear models of gene regulatory
           networks using complementarity systems
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): Vincent Acary , Hidde de Jong , Bernard Brogliato
      Gene regulatory networks control the response of living cells to changes in their environment. A class of piecewise-linear (PWL) models, which capture the switch-like interactions between genes by means of step functions, has been found useful for describing the dynamics of gene regulatory networks. The step functions lead to discontinuities in the right-hand side of the differential equations. This has motivated extensions of the PWL models based on differential inclusions and Filippov solutions, whose analysis requires sophisticated numerical tools. We present a method for the numerical analysis of one proposed extension, called Aizerman–Pyatnitskii (AP)-extension, by reformulating the PWL models as a mixed complementarity system (MCS). This allows the application of powerful methods developed for this class of nonsmooth dynamical systems, in particular those implemented in the Siconos platform. We also show that under a set of reasonable biological assumptions, putting constraints on the right-hand side of the PWL models, AP-extensions and classical Filippov (F)-extensions are equivalent. This means that the proposed numerical method is valid for a range of different solution concepts. We illustrate the practical interest of our approach through the numerical analysis of three well-known networks developed in the field of synthetic biology.


      PubDate: 2013-12-23T10:30:21Z
       
  • Conditional entropy of ordinal patterns
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): Anton M. Unakafov , Karsten Keller
      In this paper we investigate a quantity called conditional entropy of ordinal patterns, akin to the permutation entropy. The conditional entropy of ordinal patterns describes the average diversity of the ordinal patterns succeeding a given ordinal pattern. We observe that this quantity provides a good estimation of the Kolmogorov–Sinai entropy in many cases. In particular, the conditional entropy of ordinal patterns of a finite order coincides with the Kolmogorov–Sinai entropy for periodic dynamics and for Markov shifts over a binary alphabet. Finally, the conditional entropy of ordinal patterns is computationally simple and thus can be well applied to real-world data.


      PubDate: 2013-12-23T10:30:21Z
       
  • Further understanding of Huygens’ coupled clocks: The effect of
           stiffness
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270
      Author(s): J. Peña Ramirez , K. Aihara , R.H.B. Fey , H. Nijmeijer
      A simplified model of the classical Huygens’ experiment on synchronization of pendulum clocks is examined. The model consists of two pendula coupled by an elastically supported rigid bar. The synchronized limit behaviour of the system, i.e. in-phase and anti-phase synchronization of the pendula, is studied as a function of the stiffness of the spring that supports the coupling bar. It is demonstrated that the stiffness has a large influence on the existence, stability, and oscillation frequency of the in-phase solution. The relationship between the obtained results and experimental results that have been reported in the literature, including Huygens’ original observations, is stressed.


      PubDate: 2013-12-23T10:30:21Z
       
  • Analysis of bifurcations of limit cycles with Lyapunov exponents and
           numerical normal forms
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): V. De Witte , W. Govaerts , Yu.A. Kuznetsov , H.G.E. Meijer
      In this paper we focus on the combination of normal form and Lyapunov exponent computations in the numerical study of the three codim 2 bifurcations of limit cycles with dimension of the center manifold equal to 4 or to 5 in generic autonomous ODEs. The normal form formulas are independent of the dimension of the phase space and involve solutions of certain linear boundary-value problems. The formulas allow one to distinguish between the complicated bifurcation scenarios which can happen near these codim 2 bifurcations, where 3 -tori and 4 -tori can be present. We apply our techniques to the study of a known laser model, a novel model from population biology, and a model of mechanical vibrations. These models exhibit Limit Point–Neimark–Sacker, Period-Doubling–Neimark–Sacker, and double Neimark–Sacker bifurcations. Lyapunov exponents are computed to numerically confirm the results of the normal form analysis, in particular with respect to the existence of stable invariant tori of various dimensions. Conversely, the normal forms are essential to understand the significance of the Lyapunov exponents.


      PubDate: 2013-12-23T10:30:21Z
       
  • Anomalous spreading in a system of coupled Fisher–KPP equations
    • Abstract: Publication date: 1 March 2014
      Source:Physica D: Nonlinear Phenomena, Volume 270
      Author(s): Matt Holzer
      In this article, we report on the curious phenomena of anomalous spreading in a system of coupled Fisher–KPP equations. When a single parameter is set to zero, the system consists of two uncoupled Fisher–KPP equations which give rise to traveling fronts propagating with the unique, minimal KPP speed. When the coupling parameter is nonzero various behaviors can be observed. Anomalous spreading occurs when one component of the system spreads at a speed significantly faster in the coupled system than it does in isolation, while the speed of the second component remains unchanged. We study these anomalous spreading speeds and show that they arise due to poles of the pointwise Green’s function corresponding to the linearization about the unstable homogeneous state. These poles lead to anomalous spreading in the linearized system and come in two varieties—one that persists and leads to anomalous spreading for the nonlinear system and one that does not. We describe mechanisms leading to these two behaviors and prove that one class of poles are irrelevant as far as nonlinear wavespeed selection is concerned. Finally, we show that the same mechanism can give rise to anomalous spreading even when the slower component does not spread.


      PubDate: 2013-12-23T10:30:21Z
       
  • Editorial Board
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268




      PubDate: 2013-12-23T10:30:21Z
       
  • Comment on “Minimal atmospheric finite-mode models preserving
           symmetry and generalized Hamiltonian structures, Physica D 240 (2011)
           599–606”
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268
      Author(s): Alexander Gluhovsky
      Bihlo and Staufer (2011), point out that “truncation to systems in coupled gyrostats form (Gluhovsky, 2006, Gluhovsky et al., 2002) may also lead to models that retain the conservation properties of the original equations and that a single gyrostat is a Nambu system and hence using such a truncation, conservation of the underlying geometry may be implemented at least in some minimal form”. In this note, we demonstrate that example systems in Bihlo and Staufer (2011) may indeed be treated in terms of gyrostats; in particular, their central example (six-mode system (13)) proves to be a four-dimensional gyrostat.


      PubDate: 2013-12-23T10:30:21Z
       
  • Solitary waves in nematic liquid crystals
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268
      Author(s): Panayotis Panayotaros , T.R. Marchant
      We study soliton solutions of a two-dimensional nonlocal NLS equation of Hartree-type with a Bessel potential kernel. The equation models laser propagation in nematic liquid crystals. Motivated by the experimental observation of spatially localized beams, see Conti et al. (2003), we show existence, stability, regularity, and radial symmetry of energy minimizing soliton solutions in R 2 . We also give theoretical lower bounds for the L 2 -norm (power) of these solitons, and show that small L 2 -norm initial conditions lead to decaying solutions. We also present numerical computations of radial soliton solutions. These solutions exhibit the properties expected by the infinite plane theory, although we also see some finite (computational) domain effects, especially solutions with arbitrarily small power.


      PubDate: 2013-12-11T13:33:40Z
       
  • Invariant parameterization and turbulence modeling on the beta-plane
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): Alexander Bihlo , Elsa Dos Santos Cardoso-Bihlo , Roman O. Popovych
      Invariant parameterization schemes for the eddy-vorticity flux in the barotropic vorticity equation on the beta-plane are constructed and then applied to turbulence modeling. This construction is realized by the exhaustive description of differential invariants for the maximal Lie invariance pseudogroup of this equation using the method of moving frames, which includes finding functional bases of differential invariants of arbitrary order, a minimal generating set of differential invariants and a basis of operators of invariant differentiation in an explicit form. Special attention is paid to the problem of two-dimensional turbulence on the beta-plane. It is shown that classical hyperdiffusion as used to initiate the energy–enstrophy cascades violates the symmetries of the vorticity equation. Invariant but nonlinear hyperdiffusion-like terms of new types are introduced and then used in the course of numerically integrating the vorticity equation and carrying out freely decaying turbulence tests. It is found that the invariant hyperdiffusion scheme is closely reproducing the theoretically predicted k − 1 shape of enstrophy spectrum in the enstrophy inertial range. By presenting conservative invariant hyperdiffusion terms, we also demonstrate that the concepts of invariant and conservative parameterizations are consistent.


      PubDate: 2013-12-11T13:33:40Z
       
  • The scattering map in two coupled piecewise-smooth systems, with numerical
           application to rocking blocks
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): A. Granados , S.J. Hogan , T.M. Seara
      We consider a non-autonomous dynamical system formed by coupling two piecewise-smooth systems in R 2 through a non-autonomous periodic perturbation. We study the dynamics around one of the heteroclinic orbits of one of the piecewise-smooth systems. In the unperturbed case, the system possesses two C 0 normally hyperbolic invariant manifolds of dimension two with a couple of three dimensional heteroclinic manifolds between them. These heteroclinic manifolds are foliated by heteroclinic connections between C 0 tori located at the same energy levels. By means of the impact map we prove the persistence of these objects under perturbation. In addition, we provide sufficient conditions of the existence of transversal heteroclinic intersections through the existence of simple zeros of Melnikov-like functions. The heteroclinic manifolds allow us to define the scattering map, which links asymptotic dynamics in the invariant manifolds through heteroclinic connections. First order properties of this map provide sufficient conditions for the asymptotic dynamics to be located in different energy levels in the perturbed invariant manifolds. Hence we have an essential tool for the construction of a heteroclinic skeleton which, when followed, can lead to the existence of Arnold diffusion: trajectories that, on large time scales, destabilize the system by further accumulating energy. We validate all the theoretical results with detailed numerical computations of a mechanical system with impacts, formed by the linkage of two rocking blocks with a spring.


      PubDate: 2013-12-11T13:33:40Z
       
  • Symmetry breaking in the collisions of double channel BEC solitons
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): Nguyen Viet Hung , Pawel Ziń , Eryk Infeld , Marek Trippenbach
      We investigate an attractive Bose–Einstein condensate in two coupled one dimensional channels. In this system, a stable double channel soliton can form. It is symmetric for small interaction parameters but asymmetric for large ones. We study this symmetry breaking phenomenon. Next, we investigate the dynamics of symmetric double channel soliton collisions. For sufficiently strong interactions we observe spontaneous symmetry breaking during the collision. Approximate considerations based on two different methods, Bogoliubov and variational, are used to describe this effect. The results are largely compatible.


      PubDate: 2013-12-11T13:33:40Z
       
  • Exact significance test for Markov order
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): S.D. Pethel , D.W. Hahs
      We describe an exact significance test of the null hypothesis that a Markov chain is n th order. The procedure utilizes surrogate data to yield an exact test statistic distribution valid for any sample size. Surrogate data are generated using a novel algorithm that guarantees, per shot, a uniform sampling from the set of sequences that exactly match the n th order properties of the observed data. Using the test, the Markov order of Tel Aviv rainfall data is examined.


      PubDate: 2013-12-11T13:33:40Z
       
  • Stability of stationary solutions for nonintegrable peakon equations
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): A.N.W. Hone , S. Lafortune
      The Camassa–Holm equation with linear dispersion was originally derived as an asymptotic equation in shallow water wave theory. Among its many interesting mathematical properties, which include complete integrability, perhaps the most striking is the fact that in the case where linear dispersion is absent it admits weak multi-soliton solutions–“peakons”–with a peaked shape corresponding to a discontinuous first derivative. There is a one-parameter family of generalized Camassa–Holm equations, most of which are not integrable, but which all admit peakon solutions. Numerical studies reported by Holm and Staley indicate changes in the stability of these and other solutions as the parameter varies through the family. In this article, we describe analytical results on one of these bifurcation phenomena, showing that in a suitable parameter range there are stationary solutions–“leftons”–which are orbitally stable.


      PubDate: 2013-12-11T13:33:40Z
       
  • Billiard dynamics of bouncing dumbbell
    • Abstract: Publication date: 15 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 269
      Author(s): Y. Baryshnikov , V. Blumen , K. Kim , V. Zharnitsky
      A system of two masses connected with a weightless rod (called dumbbell in this paper) interacting with a flat boundary is considered. The sharp bound on the number of collisions with the boundary is found using billiard techniques. In case the ratio of masses is large and the dumbbell rotates fast, an adiabatic invariant is obtained.


      PubDate: 2013-12-11T13:33:40Z
       
  • Computation of true chaotic orbits using cubic irrationals
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268
      Author(s): Asaki Saito , Shunji Ito
      We introduce a method that enables us to generate long true orbits of discrete-time dynamical systems defined by one-dimensional piecewise linear fractional maps with integer coefficients. The method uses cubic irrationals to represent numbers and involves only integer arithmetic to compute true orbits. By applying the method to the Bernoulli map and a modified Bernoulli map, we show that it successfully generates true chaotic and intermittent orbits, respectively, in contrast with conventional simulation methods. We demonstrate through simulations concerning invariant measures and the power spectrum that the statistical properties of the true orbits generated agree well with those of typical orbits of the two maps.


      PubDate: 2013-12-07T10:26:14Z
       
  • O(2)-Hopf bifurcation for a model of cellular shock instability
    • Abstract: Publication date: Available online 4 December 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Jinghua Yao
      We study by center manifold and normal form reduction an O ( 2 ) -Hopf bifurcation arising in a simplified model of bifurcating viscous shock waves in a channel, suppressing longitudinal dependence and modeling onset of instability via competing stable/unstable diffusions. For this canonical system, a cousin of the Kuramoto-Sivashinsky model, we are able to carry out a complete bifurcation analysis.


      PubDate: 2013-12-07T10:26:14Z
       
  • Inertial focusing of small particles in wavy channels: Asymptotic analysis
           at weak particle inertia
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268
      Author(s): T. Nizkaya , J.R. Angilella , M.A. Buès
      The motion of tiny non-Brownian inertial particles in a two-dimensional channel flow with periodic corrugations is investigated analytically, to determine the trapping rate as well as the exact position of the attractor, and understand the conditions under which particle trapping and long-term suspension occur. This phenomenon has been observed numerically in previous works and happens under the combined effects of confinement and inertia. Starting from the particle motion equations, a Poincaré map is constructed analytically in the limit of weak inertia and weak channel corrugations. It enables to derive the equation of the attractor, if any, and the corresponding trapping rate. The attractor is close to a streamline, the so-called “attracting streamline”, and is shown to persist in the presence of transverse gravity, provided the channel Froude number is large enough. Particles which are trapped by this streamline can therefore travel over long distances, avoiding deposition. Numerical simulations confirm the theoretical results at small particle response times τ and reveal some non-linear effects at larger τ : the asymptotic attractor becomes unstable at some critical value and splits into multiple branches each with its own basin of attraction.


      PubDate: 2013-12-03T10:30:49Z
       
  • Propagative phase shielding solitons in inhomogeneous media
    • Abstract: Publication date: Available online 2 December 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Marcel G. Clerc , Mónica A. Garcia-Ñustes , Yair Zárate
      Dissipative solitons in parametrically driven systems propagating in a spatial inhomogeneous medium are investigated. Recently, a family of dissipative solitons with an unexpected shell-type phase structure has been reported. In the present work, we show that the phase configuration moves rigidly along with the modulus after some transient state. Such transient state is characterized for a self-adaptation of the phase front symmetry and its relative distance to the soliton. The described dynamical behavior is analytical predicted, showing good agreement with numerical simulations. A mechanism of control and manipulation of these structures based on spatial inhomogeneities is proposed.


      PubDate: 2013-12-03T10:30:49Z
       
  • Smoothing non-smooth systems with low-pass filters
    • Abstract: Publication date: Available online 3 December 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): James Hook
      Low pass filters, which are used to remove high frequency noise from time series data, smooth the signals they are applied to. In this paper we examine the action of low pass filters on discontinuous or non-differentiable signals from non-smooth dynamical systems. We show that the application of such a filter is equivalent to a change of variables, which transforms the non-smooth system into a smooth one. We examine this smoothing action on a variety of examples and demonstrate how it is useful in the calculation of a non-smooth system’s Lyapunov spectrum.


      PubDate: 2013-12-03T10:30:49Z
       
  • Response of the parameters of a neural network to pseudoperiodic time
           series
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268
      Author(s): Yi Zhao , Tongfeng Weng , Michael Small
      We propose a representation plane constructed from parameters of a multilayer neural network, with the aim of characterizing the dynamical character of a learned time series. We find that fluctuation of this plane reveals distinct features of the time series. Specifically, a periodic representation plane corresponds to a periodic time series, even when contaminated with strong observational noise or dynamical noise. We present a theoretical explanation for how the neural network training algorithm adjusts parameters of this representation plane and thereby encodes the specific characteristics of the underlying system. This ability, which is intrinsic to the architecture of the neural network, can be employed to distinguish the chaotic time series from periodic counterparts. It provides a new path toward identifying the dynamics of pseudoperiodic time series. Furthermore, we extract statistics from the representation plane to quantify its character. We then validate this idea with various numerical data generated by the known periodic and chaotic dynamics and experimentally recorded human electrocardiogram data.


      PubDate: 2013-12-03T10:30:49Z
       
  • On the stirring properties of the thermally-driven rotating annulus
    • Abstract: Publication date: 1 February 2014
      Source:Physica D: Nonlinear Phenomena, Volume 268
      Author(s): R.J. Keane , P.L. Read , G.P. King
      The stirring properties of the thermally-driven rotating annulus have not been extensively studied, despite sustained interest in the stirring properties of various geophysical flows, and the wide applicability of the rotating annulus to geophysical problems. This paper takes important steps towards a thorough investigation of the stirring properties of thermally-driven rotating annulus flows, by demonstrating numerically the utility of two stirring measures for a parameter set yielding relatively simple flow conditions. The first measure is the finite scale Lyapunov exponent (FSLE), which has been successfully used to highlight the stirring properties of various geophysical flows. The second measure is the Eulerian symmetry measure, which has been far less widely used: this second measure does not provide such a detailed view of the stirring properties as the FSLE, but is far more efficient to calculate. Both measures are shown to have some success for the simple flow case studied, providing a strong foundation for further investigation into more complicated flows.


      PubDate: 2013-12-03T10:30:49Z
       
  • Composite centrality: A natural scale for complex evolving networks
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): A.C. Joseph , G. Chen
      We derive a composite centrality measure for general weighted and directed complex networks, based on measure standardisation and invariant statistical inheritance schemes. Different schemes generate different intermediate abstract measures providing additional information, while the composite centrality measure tends to the standard normal distribution. This offers a unified scale to measure node and edge centralities for complex evolving networks under a uniform framework. Considering two real-world cases of the world trade web and the world migration web, both during a time span of 40 years, we propose a standard set-up to demonstrate its remarkable normative power and accuracy. We illustrate the applicability of the proposed framework for large and arbitrary complex systems, as well as its limitations, through extensive numerical simulations.


      PubDate: 2013-11-29T10:30:44Z
       
  • Causation entropy identifies indirect influences, dominance of neighbors
           and anticipatory couplings
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Jie Sun , Erik M. Bollt
      Inference of causality is central in nonlinear time series analysis and science in general. A popular approach to infer causality between two processes is to measure the information flow between them in terms of transfer entropy. Using dynamics of coupled oscillator networks, we show that although transfer entropy can successfully detect information flow in two processes, it often results in erroneous identification of network connections under the presence of indirect interactions, dominance of neighbors, or anticipatory couplings. Such effects are found to be profound for time-dependent networks. To overcome these limitations, we develop a measure called causation entropy and show that its application can lead to reliable identification of true couplings.


      PubDate: 2013-11-29T10:30:44Z
       
  • Editorial Board
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267




      PubDate: 2013-11-29T10:30:44Z
       
  • Evolving dynamical networks
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Igor Belykh , Mario di Bernardo , Jürgen Kurths , Maurizio Porfiri



      PubDate: 2013-11-29T10:30:44Z
       
  • Evolving networks in the human epileptic brain
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Klaus Lehnertz , Gerrit Ansmann , Stephan Bialonski , Henning Dickten , Christian Geier , Stephan Porz
      Network theory provides novel concepts that promise an improved characterization of interacting dynamical systems. Within this framework, evolving networks can be considered as being composed of nodes, representing systems, and of time-varying edges, representing interactions between these systems. This approach is highly attractive to further our understanding of the physiological and pathophysiological dynamics in human brain networks. Indeed, there is growing evidence that the epileptic process can be regarded as a large-scale network phenomenon. We here review methodologies for inferring networks from empirical time series and for a characterization of these evolving networks. We summarize recent findings derived from studies that investigate human epileptic brain networks evolving on timescales ranging from few seconds to weeks. We point to possible pitfalls and open issues, and discuss future perspectives.


      PubDate: 2013-11-29T10:30:44Z
       
  • Adaptive coupling induced multi-stable states in complex networks
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): V.K. Chandrasekar , Jane H. Sheeba , B. Subash , M. Lakshmanan , J. Kurths
      Adaptive coupling, where the coupling is dynamical and depends on the behaviour of the oscillators in a complex system, is one of the most crucial factors to control the dynamics and streamline various processes in complex networks. In this paper, we have demonstrated the occurrence of multi-stable states in a system of identical phase oscillators that are dynamically coupled. We find that the multi-stable state is comprised of a two cluster synchronization state where the clusters are in anti-phase relationship with each other and a desynchronization state. We also find that the phase relationship between the oscillators is asymptotically stable irrespective of whether there is synchronization or desynchronization in the system. The time scale of the coupling affects the size of the clusters in the two cluster state. We also investigate the effect of both the coupling asymmetry and plasticity asymmetry on the multi-stable states. In the absence of coupling asymmetry, increasing the plasticity asymmetry causes the system to go from a two clustered state to a desynchronization state and then to a two clustered state. Further, the coupling asymmetry, if present, also affects this transition. We also analytically find the occurrence of the above mentioned multi-stable–desynchronization–multi-stable state transition. A brief discussion on the phase evolution of nonidentical oscillators is also provided. Our analytical results are in good agreement with our numerical observations.


      PubDate: 2013-11-29T10:30:44Z
       
  • Complex macroscopic behavior in systems of phase oscillators with adaptive
           coupling
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Per Sebastian Skardal , Dane Taylor , Juan G. Restrepo
      Using recent dimensionality reduction techniques in large systems of coupled phase oscillators exhibiting bistability, we analyze the complex macroscopic behavior arising when the coupling between oscillators is allowed to evolve slowly as a function of either macroscopic or local system properties. For example, we observe macroscopic excitability and intermittent synchrony in a system of time-delayed Kuramoto oscillators with Hebbian and anti-Hebbian learning. We demonstrate the robustness of our findings by considering systems with increasing complexity, including time-delayed oscillators with adaptive network structure and community interaction, as well as a system with bimodally distributed frequencies.


      PubDate: 2013-11-29T10:30:44Z
       
  • Networks of theta neurons with time-varying excitability: Macroscopic
           chaos, multistability, and final-state uncertainty
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Paul So , Tanushree B. Luke , Ernest Barreto
      Using recently developed analytical techniques, we study the macroscopic dynamics of a large heterogeneous network of theta neurons in which the neurons’ excitability parameter varies in time. We demonstrate that such periodic variation can lead to the emergence of macroscopic chaos, multistability, and final-state uncertainty in the collective behavior of the network. Finite-size network effects and rudimentary control via an accessible macroscopic network parameter is also investigated.


      PubDate: 2013-11-29T10:30:44Z
       
  • Decentralized identification and control of networks of coupled mobile
           platforms through adaptive synchronization of chaos
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Nicola Bezzo , Patricio J. Cruz , Francesco Sorrentino , Rafael Fierro
      In this paper, we propose an application of adaptive synchronization of chaos to detect changes in the topology of a mobile robotic network. We assume that the network may evolve in time due to the relative motion of the mobile robots and due to unknown environmental conditions, such as the presence of obstacles in the environment. We consider that each robotic agent is equipped with a chaotic oscillator whose state is propagated to the other robots through wireless communication, with the goal of synchronizing the oscillators. We introduce an adaptive strategy that each agent independently implements to: (i) estimate the net coupling of all the oscillators in its neighborhood and (ii) synchronize the state of the oscillators onto the same time evolution. We show that, by using this strategy, synchronization can be attained and changes in the network topology can be detected. We further consider the possibility of using this information to control the mobile network. We apply our technique to the problem of maintaining a formation between a set of mobile platforms which operate in an inhomogeneous and uncertain environment. We discuss the importance of using chaotic oscillators, and validate our methodology by numerical simulations.


      PubDate: 2013-11-29T10:30:44Z
       
  • Adaptive network dynamics and evolution of leadership in collective
           migration
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): Darren Pais , Naomi E. Leonard
      The evolution of leadership in migratory populations depends not only on costs and benefits of leadership investments but also on the opportunities for individuals to rely on cues from others through social interactions. We derive an analytically tractable adaptive dynamic network model of collective migration with fast timescale migration dynamics and slow timescale adaptive dynamics of individual leadership investment and social interaction. For large populations, our analysis of bifurcations with respect to investment cost explains the observed hysteretic effect associated with recovery of migration in fragmented environments. Further, we show a minimum connectivity threshold above which there is evolutionary branching into leader and follower populations. For small populations, we show how the topology of the underlying social interaction network influences the emergence and location of leaders in the adaptive system. Our model and analysis can be extended to study the dynamics of collective tracking or collective learning more generally. Thus, this work may inform the design of robotic networks where agents use decentralized strategies that balance direct environmental measurements with agent interactions.


      PubDate: 2013-11-29T10:30:44Z
       
  • Moment-closure approximations for discrete adaptive networks
    • Abstract: Publication date: 15 January 2014
      Source:Physica D: Nonlinear Phenomena, Volume 267
      Author(s): G. Demirel , F. Vazquez , G.A. Böhme , T. Gross
      Moment-closure approximations are an important tool in the analysis of the dynamics on both static and adaptive networks. Here, we provide a broad survey over different approximation schemes by applying each of them to the adaptive voter model. While already the simplest schemes provide reasonable qualitative results, even very complex and sophisticated approximations fail to capture the dynamics quantitatively. We then perform a detailed analysis that identifies the emergence of specific correlations as the reason for the failure of established approaches, before presenting a simple approximation scheme that works best in the parameter range where all other approaches fail. By combining a focused review of published results with new analysis and illustrations, we seek to build up an intuition regarding the situations when existing approaches work, when they fail, and how new approaches can be tailored to specific problems.


      PubDate: 2013-11-29T10:30:44Z
       
  • Predicting the bifurcation structure of localized snaking patterns
    • Abstract: Publication date: Available online 19 November 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Elizabeth Makrides , Björn Sandstede
      We expand upon a general framework for studying the bifurcation diagrams of localized spatially oscillatory structures. Building on work by Beck et al., the present work provides rigorous analytical results on the effects of perturbations to systems exhibiting snaking behavior. Starting with a reversible variational system possessing an additional Z 2 symmetry, we elucidate the distinct effects of breaking symmetry and breaking variational structure, and characterize the resulting changes in both the bifurcation diagram and the solutions themselves. We show how to predict the branch reorganization and drift speeds induced by any particular given perturbative term, and illustrate our results via numerical continuation. We further demonstrate the utility of our methods in understanding the effects of particular perturbations breaking reversibility. Our approach yields an analytical explanation for previous numerical results on the effects of perturbations in the one-dimensional cubic-quintic Swift–Hohenberg model, and allows us to make predictions on the effects of perturbations in more general settings, including planar systems. While our numerical results involve the Swift–Hohenberg model system, we emphasize the general applicability of the analytical results.


      PubDate: 2013-11-21T10:19:57Z
       
  • Spiralling dynamics near heteroclinic networks
    • Abstract: Publication date: Available online 13 November 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Alexandre A.P. Rodrigues , Isabel S. Labouriau
      There are few explicit examples in the literature of vector fields exhibiting complex dynamics that may be proved analytically. We construct explicitly a two parameter family of vector fields on the three-dimensional sphere S 3 , whose flow has a spiralling attractor containing the following: two hyperbolic equilibria, heteroclinic trajectories connecting them transversely and a non-trivial hyperbolic, invariant and transitive set. The spiralling set unfolds a heteroclinic network between two symmetric saddle-foci and contains a sequence of topological horseshoes semiconjugate to full shifts over an alphabet with more and more symbols, coexisting with Newhouse phenonema. The vector field is the restriction to S 3 of a polynomial vector field in R 4 . In this article, we also identify global bifurcations that induce chaotic dynamics of different types.
      Graphical abstract image

      PubDate: 2013-11-17T10:30:49Z
       
  • Experimental investigation of colored noise in stochastic resonance of a
           bistable beam
    • Abstract: Publication date: Available online 6 November 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Dennis J. Tweten , Brian P. Mann
      This paper describes an experimental investigation of stochastic resonance in a bistable, composite beam excited by colored noise. Experimental results for average up-crossing period, spectral power amplification (SPA), and signal-to-noise ratio (SNR) are compared with analytical methods for underdamped systems. These analytical methods include expressions developed from Kramers, Melnikov, and two-state theory. The effect of a modal mass on the analytical expressions is explored. Finally, an alternative approach for calculating the effect of a colored noise spectrum on the SPA and SNR of underdamped systems is proposed.


      PubDate: 2013-11-09T10:35:14Z
       
  • Phase synchronized quasiperiodicity in power electronic inverter systems
    • Abstract: Publication date: Available online 5 November 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Zhanybai T. Zhusubaliyev , Erik Mosekilde , Alexey I. Andriyanov , Vladimir V. Shein
      The development of switch-mode operated power electronic converter systems has provided a broad range of new effective approaches to the conversion of electric power. In this paper we describe the transitions from regular periodic operation to quasiperiodicity and high-periodic resonance behavior that can be observed in a pulse-width modulated DC/AC converter operating with high feedback gain. We demonstrate the occurrence of two different types of torus birth bifurcations and present a series of phase portraits illustrating the appearance of phase-synchronized quasiperiodicity. Our numerical findings are verified through comparison with an experimental inverter system. The results shed light on the transitions to quasiperiodicity and to various forms of three-frequency dynamics in non-smooth systems.


      PubDate: 2013-11-09T10:35:14Z
       
  • Cotangent bundle reduction and Poincaré-Birkhoff normal forms
    • Abstract: Publication date: Available online 29 October 2013
      Source:Physica D: Nonlinear Phenomena
      Author(s): Ünver Çiftçi , Holger Waalkens , Henk W. Broer
      In this paper we study a systematic and natural construction of canonical coordinates for the reduced space of a cotangent bundle with a free Lie group action. The canonical coordinates enable us to compute Poincaré-Birkhoff normal forms of relative equilibria using standard algorithms. The case of simple mechanical systems with symmetries is studied in detail. As examples we compute Poincaré-Birkhoff normal forms for a Lagrangian equilateral triangle configuration of a three-body system with a Morse-type potential and the stretched-out configuration of a double spherical pendulum.


      PubDate: 2013-11-01T10:30:42Z
       
 
 
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